Feeding mechanism for sewing machines



Aug. 13; 1940. s. zoms FEEDING MECHANISM FOR SEWING MACHINES med Feb. 16, 193,9 2 Sheets-Sheet 1 zya lne y Zonis Aug. 13, 1940. s. ZONIS 2,211,633

FEEDINGMECHANISM FOR SEWING MACHINES Filed Feb. 16', 1939 2 Sheets-Sheet 2 2g l I 24 26 I:

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'ydny Zonis v Patented Aug. 13, 1940 2,211,633 FEEDING MECHANISM FOR SEWING A HINES Sydney Zonis, Bridgeport, Conn., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application February 16, 1939, Serial No. 256,653

17 Claims.

This invention relates to improvements in feed ing mechanisms for sewing machines and more particularly to feeding mechanisms of the socalled drop-feed type in which a feed-dog is 5 actuated successively to engage and advance the 'work, to relase the work and to return to initial position.

A primary object of the present invention is to provide a high speed actuating mechanism for a drop-feed feed-dog particularly effective to advance the work so as to obtain uniform lengths of stitches.

A further object of the invention is to provide a feeding mechanism of simple construction and 15 readily adaptable to meet diiferent' work-advancing requirements.

With these and other objects in view, as will hereinafter appear, the invention consists in the devices, combinations and arrangements of parts 20 described in connection with the accompanying drawings, which illustrate a preferred embodiment of the invention and in which:

Fig. 1 is a bottom plan view, partly broken away, of a sewing machine containing the pres- 25 ent improved feeding mechanism. Fig. 2 represents an enlarged vertical section of the feed-actuating mechanism, the section being taken lengthwise of the primary feed-shaft. Fig. 3 is an enlarged front end elevation, partly in sec- 30 tion, of the improved feeding mechanism. Fig. 4 represents, in perspective, detached views of the feed-bar and of the linkage mechanism actuated by the auxiliary feed-shaft.

The sewing machine illustrated in the draw- 35 ings has the usual work-supporting bed-plate i provided with a throat-plate 2 having a needleaperture 3 and feed-slots 4.

Depending from the under side of the .bedplate I are spaced bearing-lugs 5 and 6 in which 4 is journaled a substantially horizontal loop-taker shaft 1 preferably disposed medianly of the width of the bed-plate and. extending longitudinally thereof. At one end, the shaft 1 carries a rotary loop-taker (not shown), the opposite 5 end of said shaft carrying a pulley 8 connected by a belt 9 with the usual needle-reciprocating shaft (not shown) so that the loop-taker shaft 1 rotates twice for each rotation of said needlereciprocating shaft. v v

50 Also suitably journaled in the bearing-lugs 5 and 6 is a primary feed-shaft l carrying at one end a belt-pulley H which may be driven by a belt I 2 connected with the needle-reciprocating shaft so that the shaft l0 rotates at one-half the 66 speed of rotation of the loop-taker shaft 1. The

opposite end of the shaft III has a reduced eccentric extension providing a rotary feed-lift actuating element in the form of a crank-pin l3. Pivotally embracing the crank-pin l3 and held thereon by a suitable collar I4 is an apertured boss l5 at the lower end of a vertically extending link-member IS. The link-member I6 is longitudinally provided with a groove l1 slidably receiving a vertically disposed rib l8 on the head IQ of a shouldered pivot-stud 20, said pivot-stud 10 being secured to the link-member It. for ad- J'ustment endwise of the latter, by means of a screw 2| passing through an elongated slot 22 in the link-member l6.

The pivot-stud 20 is pivotally embraced by an apertured boss 23 at one end of a horizontally disposed feed-bar 24, upon which feed-bar a feeddog 25 is suitably secured by screws 26. The feed-dog 25 operates in the slots 4 of the throatplate 2 in the usual manner. 20

The opposite end of the feed-bar 24 is formed as a flattened ear 21 provided in the side face thereof with a generally vertical groove 28. Adjustably seated in said groove 28 is a vertically disposed rib 29 on the head 30 of a shouldered '25 pivot-stud 3| similar to the pivot-stud 28. The feed-bar ear 2! has a vertically elongated slot 32 entered by a securing screw 33 threaded into the pivot-stud head 30, thereby providing for vertical adjustment of the feed-bar upon said 30 pivot-stud head.

The pivot-stud 3| is pivotally embraced by an apertured boss 34 at the upper end of an angularly adjustable link-member 35' having at its lower end another apertured boss 36. The boss 35 36 pivotally embraces a feed-lift actuating crankpin 31 comprising a reduced eccentric extension of an auxiliary feed-shaft 38. The auxiliary feed-shaft 38, at one end thereof, is rotatably joumaled in the bearing-lug 5 and at the opposite end in the bearing-lug 39 which also depends from the bed-plate I. Between the bearing-lugs 5 and 39, the feed-shaft 38 carries a pulley 40 connected by a belt 4| to a pulley 42 carried by the primary feed-shaft ID, the pulleys 48 and 5 42 being proportioned so that the feed-shafts l0 and 38 rotate synchronously in one-to-one relationship.

The link-member 35 is provided with an arcuate slot 43, having the crank-pin 31 as its cen- 50 ter of curvature and receiving a securing screw 44 threaded into the upper arm of a feed-advance rock-lever 45. This arrangement provides for angular adjustment of the link-member 35 about the crank-pin 31 and thereby provides for adjusting the feed-dog 25 lengthwise of the throat-plate slots 4. The rock-lever 45 is fulcrumed between its ends upon the crank-pin 31 and to that end is provided with an aperture 45 to receive said crank-pin, said rock-lever being disposed between the link-member 35 and the crank-pin shoulder of the auxiliary feed-shaft 3B.

The lower arm of the feed-advance rock-lever 45 is connected by a pivot-screw 41 to one end of a pitman 48, of which the opposite end is formed as a strap 49 embracing a feed-advance eccentric 50. The eccentric 50 has an elongated slot to receive the shaft l0 and extends laterally from a correspondingly slotted slide-block 52. The block 52 is slidingly disposed in a diametral guideway 53 of a collar 54 secured by a screw 55 upon the primary feed-shaft directly adjacent the link-member boss l5. An adjusting screw 56, threaded into the collar 54 and adapted to engage the slide-block 52, provides means for adjusting the eccentricity of the cocentric 50 with respect to the rotation axis of the shaft l0. Adjustable eccentrics of the type above described are well known in the art, one form thereof being disclosed, for example, in the U. S. Patent to P. Diehl et al., No. 814,027, Mar. 6, 1906. It is to be understood, however, that the present invention is not to be construed as limited to any particular form of eccentric adjustment.

The parallel feed-shafts l0 and 38 are preferably disposed so that their axes of rotation lie in the same horizontal plane at opposite sides of the rotation-axis of the loop-taker shaft 1. Furthermore, the crank-pins I3 and 31 are preferably offset in the same direction from the respective axes of rotation of the synchronously rotating shafts I0 and 3B, whereby-said crank-pins are constantly in phase. Also, the substantially parallel link-members I6, 35 are preferably of substantially equal lengths between the crankpins I3, 31 and the pivot-studs 20, 3|. As the feed-shafts l0 and 38 rotate in the same direction and the crank-pins l3 and 31 are constantly in phase, the work-engaging portion of the feeddog is constantly maintained in parallelism with the plane of the work-support l. Obviously, the plane of the feed-dog teeth may be changed by vertical adjustment of one end of the feedbar 24.

The eccentric 50 is preferably offset, from the rotation axis of the primary feed-shaft iii, in the direction substantially opposite to the direction of offset of the crank-pins i3, 31, owing to the fact that in the present case the rock-lever 45 is fulcrumed between itaends upon the crank-pin 31. In other words, the eccentric is timed so that the rock-lever 45 supplements the action of the crank-pins I3, 31, upon the link-members, in directions to impart work-advancing and return movements to the feed-dog 25. Consequently, a minimum of eccentricity of the eccentric 50 is required for any given amplitude of feed of the work.

The employment of rotating feed-shafts having continuous circular motion instead of the feed-rock shafts more commonly employed in prior constructions, the minimum eccentricity requirements of the feed-advance eccentric, and the parallel motion linkage connections with the feed-bar all combine to provide a high speed and durable feeding mechanism which is particularly effective in the production of seams having uniform stitch lengths.

Having thus set forth the nature of the invention, what I claim herein is:

1. A feeding mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, a pair of synchronously rotating feedlift actuating elements having continuous circular motion about spaced and substantially parallel axes, operative connections between said actuating elements and said feed-bar for imparting rising and falling movements to said feed-dog, and means for imparting work-advancing and return movements to said feed-dog.

2. A feeding mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, a pair of synchronously rotating feedlift actuating elements having continuous circular motion, operative connections between said actuating elements and said feed-bar for imparting rising and falling movements to said feeddog, a rotary feed-advance actuating element coaxial with one of said feed-lift actuating elements, and operative connections between said feed-advance actuating element and said feed-bar for imparting work-advancing and return movements to said feed-dog.

3. A feeding mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, a pair of rotary feed-lift actuating elements having continuous circular motion about substantially parallel axes and operatively connected to said feed-bar at points spaced longitudinally of the feed-bar, and means for imparting work-advancing and return movements to said feed-dog.

4. A feeding mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, a pair of synchronously rotating feedlift actuating elements having continuous circular motion about substantially parallel axes and operatively connected to said feed-bar at points spaced longitudinally of the feed-bar, an adjustable feed-advance eccentric coaxial with one of said feed-lift actuating elements, and operative connections between said eccentric and said feedbar for imparting work-advancing and return movements to said feed-dog.

5. A feeding mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, a pair of rotary feed-lift actuating elements having continuous circular motion about substantially parallel axes, substantially parallel links operatively connecting said actuating elements with said feed-bar at points spaced longitudinally of the feed-bar, and means for imparting work-advancing and return movements to said feed-dog.

6. A feeding mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, a pair of rotary feed-lift actuating elements having continuous circular motion about substantially parallel axes, substantially parallel links operatively connecting said actuating elements with said feed-bar at points spaced longitudinally of the feed-bar, and means operatively connected with one of said links for imparting work-advancing and return movements to said feed-bar.

'7. A feeding mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, a pair of rotary feed-lift actuating elements having continuous circular motion about substantially parallel axes, substantially parallel links operatively connecting said actuating elements with said feed-bar at points spaced longitudinally of the feed-bar, a rock-lever pivotally mounted upon one of said feed-lift actuating elements and operatively connected to one of said links, and means for rocking said lever for imparting work-advancing and return movements to said feed-dog.

8. A feeding mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, a pair of rotary feed-lift actuating elements having continuous circular motion about substantially parallel axes, substantially parallel links operatively connecting said actuating elements with said feed-bar at points spaced longitudinally of the feed-bar, a rock-lever pivotally mounted upon one of said feed-lift actuating elements and operatively connected to one of said links, and a feed-advance actuating element coaxial with the other of said feed-lift actuating elements and operatively connected to said rocklever for imparting work-advancing and return movements to said feed-dog.

9. A feeding mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, a pair of rotary feed-lift actuating elements having continuous circular motion about substantially parallel axes, substantially parallel links operatively connecting said actuating elements with said feed-bar at points spaced longitudinally of the feed-bar, a rock-lever pivotally mounted upon one of said feed-lift actuating elements and operatively connected to one of said links, a rotary feed-advance eccentric, a pitman operatively connected to said rock-lever and having a strap embracing said eccentric.

10. A feeding mechanism for sewing machines comprising, a feed-bar, a feed dog carried by said feed-bar, a pair of rotary feed-lift actuating elements having continuous circular motion about substantially parallel axes, substantially parallel links operatively connecting said actuating elements with said feed-bar at points spaced longitudinally of the feed-bar, a two-armed rock-lever fulcrumed upon one of said feed-lift actuating elements adjacent one of said links, securing means adjustably connecting an arm of said rocklever to. the adjacent link, and means operatively connected to the other arm of said rock-lever for imparting work-advancing and return movements to said feed-dog.

11. A feeding mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, a pair of rotary feed-lift actuating elements having continuous circular motion about substantially parallel axes and operatively. connected to said feed-bar at points spaced longitudinally of the feed-bar, a rock-lever fulcrumed upon one of said feed-lift actuating elements and operatively connected to said feed-bar to impart work-advancing and return movements to said feed-dog, and means for rocking said lever.

12. A drop-feed mechanism for sewing ma chines comprising, a feed-bar, a feed-dog carried by said feed-bar, a pair of rotary feed-lift actuating elements having continuous circular motion about horizontally parallel axes, operative connections with said actuating elements for imparting rising and falling movements to and providing for vertical adjustment of said feed bar, and operative connections for imparting work-advancing movements to and providing for endwise adjustment of said feed-bar.

13. A drop-feed mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, a pair of rotary feed-lift actuating elements having continuous circular motion about horizontally parallel axes, vertically adjustable link-connections between said actuating elements and said feed-bar at points spaced longitudinally of the feed-bar, and means for imparting work-advancing and return movements to said feed-dog, including connections providing for endwise adjustment of said feed-bar.

14. A feeding mechanism for sewing machines comprising, a feedbar, a feed-dog carried by said feed-bar, a pair of rotary feed-lift actuating elements having continuous circular motion about substantially parallel axes, substantially parallel link-members pivotally carried by said elements, a pivot-stud operatively connected to one end of said feed-bar and secured upon one of said linkmembers for adjustment endwise of the linkmember, a second pivot-stud operatively connected to the other of said link-members and adjustably secured to the other end of said feed bar, a rock-lever fulcrumed upon one of said actuating elements, adjustable means for securing said rocklever to one of said link-members, and means for actuating said rock-lever.

15. A feeding mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, a pair of actuating elements rotating synchronously and in phase about substantially parallel axes, substantially parallel links operatively connecting said actuating elements with said feed-bar at points spaced longitudinally of the feed-bar, a member operatively connected to one of said links for rocking said links about said actuating elements, and a rotary feed-advance actuating eccentric operatively connected with said member.

16. A feeding mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, substantially parallel primary and auxiliary feed-shafts, means for synchronously rotating said shafts, crank-members carried by the respective feed-shafts, substantially parallel links operatively connecting said crank-members to said feed-bar at points spaced longitudinally of the feed-bar, a rock-lever fulcrumed upon the crankmember of said auxiliary feed-shaft and operatively connected to one of said links, an eccentric adjustably carried by said primary feedshaft, and means actuated by said eccentric for rocking said lever.

17. A feeding mechanism for sewing machine comprising, a feed-bar, a feed-dog carried by said feed-bar, substantially parallel primary and auxiliary feed-shafts, means for synchronously rotating said shafts, crank-members carried by and offset in substantially the same direction from the respective feed-shafts, substantially parallel links operatively connecting said crank-members to said feed-bar at points spaced longitudinally of the feed-bar, a two-armed rock-lever fulcrumed upon the crank-member'of said auxiliary feedshaft, means operatively connecting an arm of said rock-lever to one of said links, an eccentric carried by and offset from the axis of rotation of said primary feed-shaft in a direction substantially opposite to the direction of offset of the crank-member thereof, and a pitman connected strap embracing said eccentric.

SYDNEY ZONIS. 

